Synchronous multicentric osteosarcoma is a rare entity with fewer than 100 well documented cases in the medical literature. The disease usually progresses rapidly in young patients and slightly slower in adults. We present a case of synchronous multicentric osteosarcoma with some peculiarities in a 73-year-old woman. The diagnosis was made after postmortem examination, which underlines the importance of this procedure. This case report is accompanied by a review of the literature.